Like the R Season, Sailor Stars is divided into two arcs: The first arc (also filler) solves some conflicts from the SuperS season, and also sees the return of the Outer Senshi, Haruka, Michiru, Setsuna, and Hotaru (now reborn as a child). The second arc is the actual plot from the manga. Usagi bids farewell to Mamoru, who is going to America to study abroad. In his place comes the Three Lights, an idol trio consisting of three boys, Seiya, Taiki, and Yaten. The new enemy is Galaxia, a woman who desires to rule the entire galaxy by collecting the Star Seeds of humans. Three new Senshi appear, the Sailor Starlights, who also intend to stop Galaxia without Sailor Moon's help.

SuperS centers heavily on Chibi-usa and the Sailor Team. A new enemy, the Dead Moon Circus, has now appeared. Their motive is to find the Golden Dream Mirror that would be used to rule the world. To do this, the enemy attacks innocent victims for their Dream Mirrors and test their energy. Chibi-usa also has a new ally on her side, Pegasus. This season also sees the Sailor Senshi obtaining new powers.

Two years ago, Mitsuki Kouyama's friend, Eichi Sakurai, moved to America before she could confess her feelings to him. Though she cannot contact him, they made a promise to fulfill their respective dreams: Mitsuki wants to become a professional singer, and Eichi an astronomer. She hopes that one day her music will reach him across the world with a brilliance like that of the full moon. There is just one catch: Mitsuki suffers from throat cancer, which makes her voice quiet and singing strenuous. Her grandmother, who has a hatred of music, insists that Mitsuki undergo surgery to remove the cancer, but she refuses due to the risk of losing her voice. One day, two shinigami—Meroko Yui and Takuto Kira—appear to tell her that she only has one year left to live. This sudden revelation spurs Mitsuki into action, and she decides that with Meroko and Takuto's help, she will become a professional singer in the time she has left. Full Moon wo Sagashite follows the emotional story of Mitsuki and her shinigami friends as they discover what it means to sing—and ultimately, what it means to live. [Written by MAL Rewrite]

Chise is an ordinary schoolgirl: small, frail, and not particularly intelligent. Her greatest joy is her budding romance with her classmate and childhood friend, Shuuji. They both live in a small military town in Hokkaido, where high schoolers have few concerns other than who is dating whom and complaining about the steep climb up "Hell Hill" every day before school. One day, Shuuji and his friends make a trip to Sapporo to buy gifts for their girlfriends. A massive air raid on Sapporo that day kills thousands, including one of Shuuji's friends, and signals the beginning of a war. Fleeing from the carnage, Shuuji spots Chise, though now she has steel wings and a massive gun where her right arm should be. Against her will, she has been transformed into the ultimate cyborg weapon, capable of leveling entire cities. As the war rages closer and closer to their hometown, Chise and Shuuji's relationship is strained by her transformation, and they are left to wonder whether she is even still human. [Written by MAL Rewrite]